3D Mapping for Prostate Biopsies

SAN DIEGO, March 10 -- Prostate biopsies that sample tissue mapped in three dimensions may improve treatment planning and safely allow for a "lumpectomy" approach, researchers said.

Stage and grade revisions with 3-D mapping biopsy were substantial enough to change management for more than 70% of patients, compared with standard transrectal ultrasound (TRUS)-guided biopsy, according to Gary Onik, M.D., of Florida Hospital's Center for Safer Prostate Cancer Therapy in Orlando, and colleagues.

For tumors found with this more extensive biopsy method, targeted cryoablation achieved long-term local control without incontinence in all patients, according to a second study reported by the same group here at the Society of Interventional Radiology meeting.

"Almost every patient who is diagnosed with prostate cancer, except for those who, on their transrectal ultrasound biopsy, showed extensive high-grade disease, needs a mapping biopsy to fully evaluate their situation and treat them appropriately," Dr. Onik said.

Brian Stainken, M.D., of Roger Williams Hospital in Providence, R.I., and SIR president, agreed that the promising findings could be "game changing."

However, he sounded a note of caution in response to Dr. Onik's enthusiasm by emphasizing the need for further validation.

Dr. Onik, anticipating this argument, noted that the low morbidity rate -- no incontinence and 15% impotence in his study -- has been replicated in two other published studies.

These results were more impressive given that more than half of his 120 cryoablation patients with one to 13 years of follow-up were moderate- to high-risk or radiation failure cases, he said.

Likewise, morbidity was minimal with the 3-D mapping biopsy. The only complications were self-limiting hematuria (1.2%) and retention (7%).

These biopsies were done under transrectal ultrasound guidance, with tissue sampled every 5 mm throughout the prostate volume, using a brachytherapy grid. Careful labeling of specimen coordinates allowed the radiologist to reconstruct a detailed picture of the extent and location of the tumor.

Dr. Onik's group used this biopsy method for 180 men who were considering conservative management based on prior standard transrectal ultrasound biopsy that showed unilateral prostate cancer.

But the more extensive 3-D mapping biopsy showed bilateral disease in 55% of patients and increased the Gleason score for 22%.

The researchers estimated that at least 70% of the patients would have a change in therapeutic decision based on the more accurate staging.

It wasn't surprising that this technique beat transrectal ultrasound biopsy, Dr. Onik said. Although the gold standard for prostate biopsy, "we have known for decades that this is not an accurate way of staging prostate cancer," he said, "but it was the only thing we had."

In addition to helping patients decide between watchful waiting and more aggressive therapy, pinpointing the tumor can allow for a more nuanced treatment approach similar to the revolution in breast cancer surgery, Dr. Onik said.

"More than 25 years ago women were in exactly the same situation men are in now," he said. "The treatment was radical mastectomy."

With this as an inspiration, Dr. Onik's group started to pursue what he called "male lumpectomy" with focal cryoablation informed by 3-D mapping biopsy.

With this approach, their study showed that among the very high-risk radiation failure patients, 81% maintained stable prostate-specific antigen levels during follow-up after focal treatment.

In the total cohort, stable PSA rates with no evidence of cancer were reported for 93% by ASTRO criteria and 94% by Phoenix criteria.

Overall, eight patients were retreated to yield a 100% local control rate with targeted cryoablation.

Regardless of the risk level of prostate cancer patients, the biochemical recurrence rate did not climb over time and compared favorably to the 55% rate at 10 years in a prior study of high-risk patients who had radical prostatectomy.

Potency was maintained in 85% of patients potent prior to the procedure and of 120 patients without previous prostate surgery, all were continent (no pads).

Although local control has been thought to have little impact on overall survival in prostate cancer, Dr. Onik said that recent evidence has shown that better control of cancer in the prostate reduces risk of distant metastases and mortality.

The next step will be to compare "male lumpectomy" to robotic radical prostatectomy, he said.

Primary source: Society of Interventional Radiology

Source reference:

Onik G, et al "3D prostate mapping biopsy has a potentially significant impact on prostate cancer management" SIR 2009; Abstract 198.

Additional source: Society of Interventional Radiology

Source reference:

Onik G, et al "Focal therapy for prostate cancer -- 120 patients with up to 12-year follow-up" SIR 2009; Abstract 75.

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Biopsy Explained

Thursday 25/10/2007 - 4:30pm.

Attended the Urologist's Surgery to receive the results of the transrectal biopsy. As predicted, the cancer was not contained in the prostate. I was then given the shattering news that I had 'advanced and incurable prostate cancer' and was told that the only real treatment option was hormone therapy.

I was told that the cancer was very agressive with a 'Gleason Score' of 9. The Gleason score (the most commonly used biopsy grading system) indicates whether the cancer is slow or fast growing depending on a score out of 10. The higher the score, the faster (more agressive) the cancer.

After pressing for a prognosis that I could understand i.e. 'how long have I got'; I was told the following:-

Under a 'best case' scenario, I was informed that I could expect to live for a further 3 to 5 years. However, if the 'worst case' scenario were in play then I could look forward to just 12 to 18 months.

It was then determined that further tests be undertaken, including a CT scan and a Bone Scan, in order to determine the most appropriate treatment options.

Trans-rectal Biopsy

Monday 22/10/2007 - 8:45am.

Attended the Monavale Pathology Unit to undergo a 'transrectal ultrasound/biopsy'.

Ultrasound imaging, also called ultrasound scanning or sonography, involves exposing part of the body to high-frequency sound waves to produce pictures of the inside of the body.

Ultrasound exams do not use ionizing radiation (x-ray). Because ultrasound images are captured in real-time, they can show the structure and movement of the body's internal organs, as well as blood flowing through blood vessels.

Ultrasound imaging is usually a painless medical test that helps physicians diagnose and treat medical conditions. The prostate or transrectal ultrasound provides pictures of a man's prostate gland. It is a minimally invasive ultrasound because it sends sound waves through the rectum.

Ultrasound Equipment

Ultrasound scanners consist of a console containing a computer and electronics, a video display screen and a transducer that is used to scan the body.

The transducer is a small hand-held device that resembles a microphone, attached to the scanner by a cord. The transducer sends out a high frequency sound wave and then listens for a returning sound wave or "echo."

The ultrasound image is immediately visible on a nearby screen that looks much like a computer or television monitor. The image is created based on the amplitude (strength), frequency and time it takes for the sound signal to return from the patient to the transducer. For ultrasound procedures requiring insertion of the transducer, such as transvaginal or transrectal exams, the device is covered and lubricated.

Transrectalultrasound

A painless procedure in which an instrument is inserted into the rectum and sound waves bounce off the prostate, producing a picture of the prostate which can be used to help identify abnormal areas requiring a biopsy. If the results of the transrectal ultrasound are normal, you may be able to wait and repeat the PSA test a few months later and then have a biopsy if needed.

Figure 2: Transrectal ultrasound

Biopsy

In this procedure a sample of cells, tissue or fluid is removed from the prostate and viewed under a microscope, to check for signs of the disease. There are two types of biopsy:

Transrectal biopsy: a needle is inserted through the rectum into the prostate and a sample of prostate tissue is removed.

Figure 3: Transrectal biopsy

Transperineal biopsy: a needle is inserted through the skin between the scrotum and rectum into the prostate and a sample of prostate tissue is removed.

Both biopsy procedures are short and you can usually go home the same day. A biopsy is the only way to confirm or diagnose the presence of prostate cancer.

If you have been diagnosed with prostate cancer, your specialist may want to carry out some further tests to find out if the cancer has spread to other parts of the body. The results of these tests help your doctor to decide which is the best type of treatment for you.